I’ve just bought a Logitech M205 wireless notebook mouse. Like my older MX650, this mouse uses the 27 MHz spectrum. The wheel doesn’t tilt, but it has a power switch and you can stow the receiver on the underside of the mouse. So far I’m very happy with it as a travel mouse. I’ll keep the MX650 for my regular work desk.
It seems Logitech is going entirely to 2.4 GHz for their mice. This is very disappointing, as the spectrum is so crowded. I’d love to switch, but the interference problems with wifi are horrible. The tiny “unifying receiver” used by their new devices is pretty slick too, but I doubt you could put an effective 27 MHz antenna in such a small dongle. Does anyone make a modern mouse which doesn’t use 2.4 GHz or bluetooth?