Okay I've done a lot more research on this and apparently it is possible to control SlingPlayer with a MC remote using software such as
IR Server Suite to translate IR signals to key presses.
On the subject of AV senders 5.8Ghz senders exist which shouldn't interfere with or be interfered with by Wireless/Phones/Microwaves/etc.
Not sure which I'll go for. Prob a standard AV sender due to the higher cost of Slingboxes.