Best way to spend $1000 on used bookshelf speakers?

Proac Response 2 would be a great match considering the amp & desire to rock out with something small...not often easy to do. Since they are an older model $3K originally, used ~$1K is possible. Looking for 2 seconds, I found: https://reverb.com/item/45210640-proac-response-two-s-speakers-free-shipping-in-original-boxes-to-co...

Cheers,
Spencer

May take some time but Ref 3A de Capo i's can be found for around $1000

See Underwoodhifi END OF SUMMER SALE 

  LSA-10 Signatures Only $999.00 a pair Our lowest price ever Save $1500.00 36Hz bass from a monitor that sounds like a floor-stander

+1 @tweak1 on the LSA-10 Signatures — that’s a ton of excellent speaker for that price. 

I acquired a large monitor I had enjoyed years ago when reviewing it for Dagogo.com, the Wharfedale Opus 2-M2. It has similar wonderful 3" soft dome midrange that has appeal in the ATC and PMC speaker lines. I got my pair for $750 and have them mated to subs. I bought them specifically for the 3" midrange, because that sound cannot be duplicated by other smallish bookshelf speakers using different configurations. Now, I have a dynamic speaker utilizing the 3" soft dome mid and it is set up to perform as a larger floor stander. Nice result, as envisioned.  Best inexpensive speaker system I have used in quite a while. 

The Opus 2-M2 is rare around here. I hadn't seen one for several years, so when it became available, I moved quickly. To obtain similar outcome you may wish to consider an older PMC or ATC speaker.