Gonna be hard to route out a t-molding slot without taking the whole thing apart. You want the router to rest on the surface of the board and the board to be pretty stable. You try to route it assembled like that and the board will flex and shake and it will be impssoible to control the router and get a good channel cut.
Don't buy stuff off of ebay, just order direct from the vendors on this site. If you are going 4 players, you can get an ipac from andy at ultimarc.com and I think divemaster is the US vendor here in the US.
You can also order a LONO from paradise arcade, I just tried out the board, its super simple to set up.
check out my build in my signature to see what I have made, and if you are thinking about something similar let me know.
I ended up going with veneered ply in my build. Thought about laminate in the early going, but couldn't find any locally, and form looking around, it was expensive.