How much are you willing to spend on stealth mics? There are various solutions ranging from $90-2000
How stealthy do these have to be?
You can get a pair of mics the size of your pinky finger's nail, or you can get a special setup with the caps of your current mics. Possibilities: Audix 1245/90, AKG/Neumann/Schoeps/MBHO active setup, DPA 406X, DPA 402X, Audio Technica AT853. There are also some low end options from CoreSound, Giant Squid, and Dynamic Audio. Sound Professionals offers various setups using Audio Technica mics with battery boxes. Have anything in particular in mind
If you can stealth the UA-5, more power to you. A lot of people run a smaller box such as the Sound Devices mp-2, Sonosax sx-m2, EAA psp-2, AETA psp-3, Denecke AD-20, GP DMIC-20, etc.