Currently own:
Mesa Dual Rectifier - Revision C
Mesa Triple Rectifier - Revision F, "Blackface"
Mesa Stiletto Deuce Series II
Mesa Mark V (Ordered)
Mesa 4X12 (Traditional, Straight) w/V30's
Previously owned:
25+ Mesa Rectifiers (2/3 Channel, Rackmounts, etc)
3 Mesa Mark IV's
2 Mesa Mark IIC+ Heads
6 Mesa Triaxis Preamps
3 Mesa 2:90 Power Amps
2 Mesa 50/50 Power Amps
1 Mesa Strategy 400 Power Amp
2 Mesa Stiletto ACE Head Units
1 Mesa Stiletto Deuce Series I (later Hollywood Modded)
1 Mesa V-Twin
1 Mesa 4X12 (Oversized, Slant) w/V30's
2 Mesa Studio Preamps
1 Mesa Quad Preamp
2 Mesa 2X12 w/V30's
2 Mesa Mark III's (Blue and Red Stripe)
And I've bought 3 more Rectos since I made that list a couple weeks ago...
In all, I've probably owned 45+ Mesa head units, 10+ preamps, 6+ power amps, and 4 or 5 cabs. This is just rough approximates from counting up, I don't have an exact number. Lots of gear was compared to other pieces over time, and I used just about all of that in band context at some point in time.
I've PLAYED much more Mesa gear than that before. That's just a list of what I've personally OWNED.