First of all let me make this clear.....I love tubes and there sure are many that would fit the bill. However , base on my experience with Red Wine Audio gear and your small foot print (and since it is for 2nd system in the bedroom) requirements , I would suggest to take a close look into RWA Sig 30 or 30.2 integrated amp. It sounds sweet and musical....., something that is one of my preferances. Runs on batteries, is rated at 30wpc, no heat, dead quite and very small size. Perfect bedroom int. amp.
Good luck
Mariusz
Good luck
Mariusz