I bought a Sunn 412L cabinet in the DFW area recently in near mint condition, 9 out of 10 I'd say, just because of a small tear in the tolex on the top of the cab. The 2nd owner bought it a Zoo Music back in the late 70s, rehearsed on it but never did any gigs, whereas afterward the cabinet was stored with no further use. I bought it for $300 and have been rehearsing/gigging on it for the past 2 months with no problems...just thought I'd chime in for reference on pricing.
Good luck!