I am looking for a definitive list of DTE equipment that can
communicate with a v.35 interface from a csu/dsu device.
This list of equipment will hopefully help me learn about the specific
models of equipment that are used at the consumer end of a T1 connection.

Specifically I am looking for inexpensive routers (LAN or
WAN) and also I am looking for a method to connect a v.35 interface to
a PBX (maybe some sort of v.35 to DSX-1 interface?)

Old Cisco models came default with V.35 interfaces (i.e. 2500 series).
 I am not sure how many PBX's handle V.35 native, most utilize "line"
channels on CSU/DSU's (CAT5 cable).  Newer PBX T1 cars are CSU/DSU
built-in.

Good Luck!