Just bought a wireless sensor bar from Virgin. It's a
4Gamers model and only cost a tenner

.
The bar is about 3 times as heavy (with batts) as the one packaged with the Wii and twice as thick. The bonus is that it's also quite noticeably brighter...perfect for big rooms.
It uses 6 AA batteries (gives you 9V but will last a lot longer than a square 9v battery.....claimed as 30 hours continuous).
The on/off switch doubles up as an LED indicator (in the obligitary Wii Blue

) which is hard to miss.
Also comes with a (larger than standard) see through stand (which is why it appears to be levitating in this shot

).
Played a few games of Mario Strikers, Wii Sports and also mucked around on the home menu and it appears to give nice stable/solid light sources for the remotes to key on whenever you need the pointer functions.
Overall, not bad at all for a mere £10 and solved my problem nicely

.
Also looks quite "standard" like the nyko one so doesn't look out of place in a home cinema setup:
I recommend it if you're in need of a solidly built, cheap solution for projector use.