Recommendations for under-cabinet/compact amp?

I have need for an under-cabinet amp, and separately, need or an amp that would fit in a small bookcase. The first is for me. I seek to mount David Visoniks under a kitchen cabinet, and mount an amp in between them (preferably integrated, but possibly separates if small). The second would be for my father, who now needs a compact size that would fit on a bookcase. Although the kitchen system would not be for hi-fi listening, we are used to hi-fi in our other systems, and low quality would be noticeable. New or vintage, interested in all. Budget 1,500 or under, preferably under 1k each. All thoughts appreciated. 

PS Audio Sprout 100.
+1 on the Sprout.
Extremely difficult to do better in same size.
any Class D where heat is a non issue.
I’d also go with a Sprout 100 in the kitchen.  If better quality is needed/wanted in the other system there’s a NuPrime IDA-8 here now for $700 or for a little more I’d look for a used Bel Canto C5i.  Best of luck. 
I wanted to thank everyone for their responses, right on-point and useful. I orderd and NAD D 3020. It was an impressive device, but it did not offer the full-bodied, analogue sound to which am I used. I would have kept it and been satisfied that it fulfilled its intended purpose but decided to try a Rega io. Purchased one and loved it immediately. Let it burn in for four days. (Runs remarkably cool for being Class A/B.) Paired with an Audio Engine B1 for bluetooth, and tested with late-sixties Grundig towers (Lautscprecher 425) and a Cizek subwoofer (SW-SW). Dynamic, full sound, somewhat edgy on some highs, but otherwise delightful and non-fatiguing, and very detailed without sounding digital or overly analytic. Not an ideal speaker pairing, simply used what was nearest to hand and the least nuisance to hook up from among current optoins. Look forward to trying the NuPrime or Bel Canto in future, but the Rega is quite sufficient and pleasing for the purposes. For the money, someone could not go wrong with the NAD D 3020, but the Rega io was hands-down winner. Rega saved money by not including a bluetooth receiver or a DAC, so those are additional expenses.