I luckily have a LFS here in San Diego that has a "tank guy" that can make any size rimless you want, black silicone and all. Though I'm even more excited they are going to be caring ADA tanks, and products very soon as well. (no shipping costs!!!)
Check with you LFS, they might know someone who makes custom tanks.
I think the ADA tanks are beautiful........ly overpriced. ADA has become almost a religion in the aquatic community. Like they have some mystical properties which no other can duplicate. If I had the money I would be all over the ADA products, but to setup 1 of their medium cube gardens I could completely setup and stock 3-5 "standard aquariums".
Now I'm not hating, as I love their stuff, very inspirational, just constantly shocked at the mark-up.
I think DIY is the future of these rimless tanks. I personally believe that anybody can make a decent small tank, rimless or not. I am going to look for a glass cutter today and see myself how much of it is "specialized craftsmenship" and how much of it is marketing hulabahoo.
Once you get this setup off the ground, check out http://www.greenleafaquariums.com/ for some very Amano-esk glass works at half the price. They're also a forum sponsor:supz:
If Glass Cages would ship to Oregon, I would buy from them instead.
http://www.fishtankfactory.com/ is another good source of rimless tanks. I have seen one of theirs, and a couple of Glass cages tanks. Glass cages runs a distant second to Charlie's. They use very nice ground bevels on their tanks, neat thin silicone joints, and they will make any size you want.
Do you know if Charlie will ship his tanks? Glasscages will only ship to certain areas, otherwise you have to drive somewhere that they will be and pick it up. Not overly fond of that option myself.....