Tre plays a custom guitar made by Phish soundman Paul Languedoc. Bassist Mike Gordon plays a bass made by the same luthier. You can get your own Languedoc at the link below. These are not cheap and I believe the wait for them is quite a long period of time as well;
http://www.languedocguitars.com/
If you like Phish, please check out these other bands as well;
Umphrey's McGee
.moe
The New Deal
New Monsoon
Yonder Mountain String Band
The Derek Trucks Band
Douglas Showalter