@PaChalski
I have mentioned it before in this thread, and I noticed you had responded to the thread on [h] about looking into this...
Pedestals...!
Some way to get more clearance for venting from below...
I imagine three different Pedestals; S, M, & L...
Pedestals would have 10mm wide 'feet', 20mm tall cutouts / vents with a 20mm radius where the panel / vent becomes the 'feet'...
S - 37mm height, room for two slim (15mm thick) fans...
M - 47mm height, room for two standard (25mm thick) fans...
L - 77mm height, room for 240mm AIO...
I would have cutouts / vents on all four sides, but the Pedestal might also be a good way to bring front I/O into the mix (keeping the I/O down low), so cutouts / vents on three sides for I/O option models...?
Since the TopHats are modular (four corner pieces, two short front & back panels, & two long side panels), Pedestals would be the same... This means the switch to front I/O would be swapping out one short panel to the front...
Along with Pedestals, mix it up a bit on the bottom panel for the chassis...
Current bottom panel is the one with rectangular venting & slots for attaching fans...
How about a model that has cutouts for 120mm fans (circular openings, for maximum airflow) but blocks off everything else...
This 120mm fan specific model could be included with the S & M Pedestals, the L Pedestal would use the included stock bottom panel from the stock chassis...