Ked, I could easily imagine wanting a Schopper 124, PTP Solid 12 and Torqueo for different flavours of idler; SP10R, Kodo The Beat and NVS for DD; Spec GMP-8000, Kuzma Stabi M and AS-2000 for belt.
Then again, I love NAT, Koda and Ypsilon.
Zu, Apogee Duetta Interstella and Cessaro Liszt.
You get my drift.
I do look in awe at guys like Gian and Shakti who really do run multiple tts and esp carts, even those guys like Mike L running to two alternatives.
In the real world where finances are tighter, or space is an issue, a single tt/arm/cart is still going to be the norm.
For me I can't ever see myself on a daily basis accommodating more than the one rig.
And so for me, within the parameters I've set myself, I'd like to settle on the one rig, whether it's my current one, or something like the Spec/SAEC.