I have two Will-burt penumatic masts for sale.  You just don's see these things very often.
Both are in good shape, but might need a set of seals.
One is like you see in TV trucks, 6' raising to 27'.
The other is a much more rugged/wx proof model, 7' raising to 30'
For folks here, the 27'er is $1200, and the 30'er is $2400.
You can check eBay for comps.
They are listed at other prices on Craig's list at
http://atlanta.craigslist.org/nat/for/4415143594.html
and
http://atlanta.craigslist.org/nat/for/4415156767.html