None that aren't going to be a complete pain. The problem is that they all have tubing that's too long and no rotary fittings on the rad. The stock unit quite taylor made to the H1.
Only viable option would be a custom loop, but at that point you're better of just going for a different case.
There are 2 very similarly size and footprint cases, the B-Team Lab BB1 is in pre-order right now and the Mechanic Master T12-TG can be ordered off Taobao. Both can fit 240mm AIO's/rads.
Also the currently titled "Mesh-Licious" which is a mainstream vertical case that's also about the same size and has 280mm AIO/rad support. Its currently in production and should enter stores sooner or later
Then there's the Sliger SV540, which is a little bit bigger but can also fit a 280mm AIO/rad.
The H1 is a good if you use it as is, the PSU/CPU-cooler config is really meant to remain stock. Only thing you can really mess with to improve thermals are the front and rear panels.