I doubt if a tele is going to have the coverage for 8x10 though I could be wrong. I don't know of any telephotos that small that will cover.
Check Midwest and KEH for used lenses. There were a couple of good bargains in the past few weeks on the Large Format Forums. Also, you can find some good buys on ebay occasionally.
Lenes boards are interchangeable on the Toyo 8x10 and matches the Toyo 4x5... The G models are their best camera and I would only get that....Bellows as well will fit the front of a Toyo 8x10..
See my ad for a Toyo adapter plate to Graphic lensboards if you want a really hot set up for lenses on the Toyo system...I also have a Wide Angle bellows, additional bellows, wide angle bellows. Extra extension rails, and rail clamps...