op amp driven reverbs are very common, PV typically used a dual 4558 and there are kits available (google amp reverb kit)
FYI the Belton BTDR-1H digital reverb module is tiny, cheap and VERY well reviewed, and an easy op amp circuit is available.
Reviews here:Belton BTDR-1H Digital Reverb Module
Belton DigiLog Reverb ?(neunaber technology - WET? Effects Pedals)?
kit:General Guitar Gadgets - Reverb Complete Kit