I need 2.5mm thick boards. Seeed studio lets you go up to 2.0mm thickness however I need 2.5mm. This is a small prototype run. Low volume, small board, I will assemble myself.
Check out Candor Industries (www.candorind.com). We deal with them directly:
Yogen Patel (President)
I just checked with him and they do let you specify thickness of 2.5mm for small batches. It might help with pricing if you tell him I pointed you in his direction.
I use JetPCB (jetpcb.com) and really love their service. The quality and speed is great and they have a lot of options for small batches, including 2.5mm (although their “promo” pricing doesn’t include most options).