[SixClub] swap.qth.com 6M Repeater for $300.

[KB0NLY]

Actually I think you got that backwards....

"Horizontal seperation is not going to be far enough because you couldnt get
the antennas HIGH enough to make them work well."

Should be vertical, antennas at two heights.

"Vertical seperation is going to need a fair distance, if you had access to
2 towers across town from each other....."

Should be horizontal, distance between two antennas.

An easy way to do it without a duplexer is split site with a UHF link 
between the two sites.  Of course you need miles of horizontal separation.