I feel your pain, brother. I am 6'4" and I too cannot find any highway pegs that don't cost me an arm and a leg. The Kuryakyn Offset Longhorn work pretty well when mounted on the forward vertical leg of the engine guards. They offer a fair amount of forward and rearward adjustment. But, they cost an arm and a leg, IMHO. A friend of mine, (Shorty, here) had them on his '87 and he is even taller than me and he swore by them Longhorns. But one big caveat (for me): he removed the lowers from the fairing to allow his legs to stay close to the bike when his feet were on the highway pegs. I really like the lowers on the First Gen and don't want to lose their benefits.
There is a thread here talking about the leg room in general on the First Gen, with a bit of talk about the highway pegs.
Here is a photo of Shorty's bike with Kuryakyn Longhorns. You'll have to look closely, though.