This is Virtual TI 2.5 Beta 5 + some useful developer-oriented modifications by Julien Muchembled, who also authored e.g. UniversalOS for the TI-68k series. I used this version for years before TIEmu became a usable emulator. It does not fix most of VTI's accuracy bugs and emulation capability limitations, but improves the debugging experience :)

Other sites from which this version could be downloaded seem to have disappeared years ago, so I'm re-uploading my copy of the binary. I don't have a copy of the source code, sorry; I'm not sure it was published, in fact.

NOTE: this version supports an external "rc68k.h" file for user-defined ROM_CALL tables, and two such files are provided: the original one provided by JM, and my improved one resulting from reverse-engineering work. However, in this version, the usage of some breakpoint types interferes with save states. You should probably use http://ti-pla.net/a2620821 instead, unless you're prepared to deal with the fallout of this version, e.g. because you don't use save states.