Intent of this thread is to provide a place for ideas and concepts for ITX laptops. Ill start by documenting every viable idea I've run by to make such projects feasible.
The choice of motherboard to use for projects like these seem to be between the Thin-ITX standard or Mini-ITX standard. Both options seem to have their pros and cons but are equally viable options in my opinion. A basic rundown of the two below goes as follows:
Thin-ITX is beat suited for projects like these out of the box. They use SODIMM memory slots, making them much more compact. They often feature eDP or LVDS connectors which allows for LCD panels to be used for a monitor. They also feature DC jacks which allows powering these things much easier, 4 pin power connectors are also available for any potential battery systems. The main downside of thin-ITX however is that they're primarily meant for industrial use so they rarely see commerical markets. They're also dominantly intel boards, very few AMD options exist, with most not being for commercial sale. All in all one's main struggle with Thin-ITX is going to be getting one in the first place, but once obtained it'll prove a good solution to most problems these builds suffer.
Mini-ITX on the other end is practically a polar opposite. Getting ahold of one is very easy, however the board itself will most likely need modding to fit the needs of this project. The average mini-ITX board tends to have a very bulky I/O, so unless we want to build cinderblock laptops we'll need to remove most of the I/O either via desoldering methods or as Socket Science did, yanking them off. Losing the entire I/O is a bit problematic however plenty of solutions exist to restore functionality, such as using the USB header connectors meant for a chassis to install USB hubs. Very few Mini-ITX boards feature eDP/LVDS however fortunately there are PCIe cards that offer thunderbolt USB-C, which could be used as a means to get a connection to a display, certain video cards most likely also feature such options. For power, the typical 20/24 pin connector is going to be our option here. Pico-PSUs exist as a simple solution, and UPSs by Mini-Box also seem to offer potential solutions.
Thin-ITX is beat suited for projects like these out of the box. They use SODIMM memory slots, making them much more compact. They often feature eDP or LVDS connectors which allows for LCD panels to be used for a monitor. They also feature DC jacks which allows powering these things much easier, 4 pin power connectors are also available for any potential battery systems. The main downside of thin-ITX however is that they're primarily meant for industrial use so they rarely see commerical markets. They're also dominantly intel boards, very few AMD options exist, with most not being for commercial sale. All in all one's main struggle with Thin-ITX is going to be getting one in the first place, but once obtained it'll prove a good solution to most problems these builds suffer.
Mini-ITX on the other end is practically a polar opposite. Getting ahold of one is very easy, however the board itself will most likely need modding to fit the needs of this project. The average mini-ITX board tends to have a very bulky I/O, so unless we want to build cinderblock laptops we'll need to remove most of the I/O either via desoldering methods or as Socket Science did, yanking them off. Losing the entire I/O is a bit problematic however plenty of solutions exist to restore functionality, such as using the USB header connectors meant for a chassis to install USB hubs. Very few Mini-ITX boards feature eDP/LVDS however fortunately there are PCIe cards that offer thunderbolt USB-C, which could be used as a means to get a connection to a display, certain video cards most likely also feature such options. For power, the typical 20/24 pin connector is going to be our option here. Pico-PSUs exist as a simple solution, and UPSs by Mini-Box also seem to offer potential solutions.
Choosing between intel and AMD CPUs is dependant mostly on your goals and choice of motherboard. AMD offers a good choice of APUs which actually perform not bad in benchmarks, thus if you're aiming to avoid installing a dGPU they're your best bet. Intel is pretty much your only option for Thin-ITX, and although Arrow Lake is supposed to feature some serious iGPUs, its a completely new socket and therefore will require new Thin-ITX boards be released, best of luck to anyone planning to get their hands on one. The most realisitc option for Thin-ITX is most likely using a dGPU and removing its stock heatsink. Once more pointing to socket science this is a viable option, just requires handiwork on the builder's part.
Probably the hardest part to work out for builds like this is how exactly will powering the system work? Mini-Box has a few solid options for battery systems such as OpenUPS, or on the flipside devotion laptop proved that custom building a battery system is also possible. Of course, there is also the option to omit the battery, reducing the portability of a device meant to be portable by nature, but certainly a way to simplify the build.
Regardless of which motherboard chosen utilizing the USB headers to add USB connectors for a keyboard and trackpad is an option, depending on the model of keyboard wirless is even an option. Some options even offer headphone jacks but its difficult to say how good they actually are. Beyond that many commerical solutions exist for other things, power buttons that are simply as-is and not connected to a chassis exist. Some of these expansion bays offer SD card slots, and depending on how much cablework you want going on inside internally a CD drive is even possible. For displays thin LCDs that use eDP or LVDS is easily the best option for thin-ITX. But plenty of slim displays exist for mini-ITX too in the form of thunderbolt 4 USB-C connectors.
