I made my own tanks...with a little help. Total cost was under $200.
I bought some 2x4" and 4x4" aluminum square stock and 1/8" plate on eBay, also ordered 2 radiator necks, a handful of aluminum weld bungs, brass pipe fittings and caps.
I had a local guy weld everything up, did a nice job and was dirt cheap (charged me $100 for the tanks and chargecooler).
I think they look way cooler than the round stock tanks, they're a little longer than the stock ones and the square shape adds some volume too.
I used PEC compression fittings to mount the sensors...slipped a short piece of the plastic tube over the sensor for electrical isolation, inserted the tube into the fitting and snugged it up with the compression nut...way better than the OEM rubber grommet.