AETHERPHON, global theremin family

Hello.

Currently I am running my pitch-preview signal thru an inexpensive Radio Shack
amp, an in-line volume control, and an earbud.

This arrangement is working well for me however I would prefer a wireless
arrangement for the pitch preview.

As you can imagine, I don't need a great range on this because the distance from
the transmitter (at the base of the Theremin) and the receiver (which would be
somewhere on me) will only be a few feet.

Wireless monitors run from around $80 (on ebay) up to around $800 (expensive,
retail models).  My questions are:

1) Does anyone have recommendations and experience with wireless in-ear monitors
to share?

2) Does the wireless setup create interference or noise problems?

3) Will a wireless setup work in a venue that is using other wireless mic's or
other devices?

Any info much appreciated.  Thanks!

-- Kevin