Would these fit spec-wise?:
Size (HWD) in cm: 22.0 x 15.0 x 20.0
Mass per speaker: 3.2Kg
Frequency Response: 65Hz-28kHz (+/- 3dB)
Sensitivity: 88 dB/W
Impedance: 8 ohms (nominal) / 6 ohms (minimum)
Size-wise, they fall within your limits
While they might lack LF extension, the mids and highs are excellent.
Sensitivity & impedance give a relatively benign load
If yes to above question, the only potential issue is that they have been discontinued but may still available from dealers as NOS.
What are they? Acoustic Energy Compact 1 bookshelf speakers
I have three pairs and am very happy with them - the first pair was paired with a Topping chip amp fed from a desktop PC and I was so pleased with the result, I bought another Topping/AE set for the other desktop PC. Then I got the wife a Denon DM40 and, after letting her play with the one desktop audio setup, she liked the AEs so much, she demanded a pair for the Denon.
Here in South Africa, the AE distributor went belly-up and another local dude picked up the distributorship and then went around all the dealers and bought back the inventory of discontinued product. He then used this inventory at very attractive pricing to help build brand awareness and acceptance - hence the three pairs (local price equivalent in Sterling: GBP140.00 / pair).
Worth auditioning...
Dave