If someone wanted to set something like this up relatively inexpensively, look around for used Zetron Series 4000 consoles; I've seen them going for reasonable prices on eBay and Govdeals. One of the offerings (I think the 4010) is a desktop unit with all the interface hardware built in, so all you need to do is run phone wires (CAT5 works fine) from the radios to the desktop console. Alternatively, a full Series 4000 installation with Common Control would give you loads of flexibility, and it's relatively easy to set up; a typical common control will have a system card, two console cards, and the necessary number of radio interface cards for the number of channels (two radios per card, so the 4008 has four cards, the 4016 has eight cards, etc).
The Series 4000 is programmable so you can define the buttons to do all sorts of stuff, including channel up, channel down, A/B channel, etc etc. Also does paging, which when using a simplex channel (and properly identifying) can be a fun way to entertain yourself on a cold winter day ("let's see, how many different paging tone combinations can I come up with in the next 5 minutes?").
If you wanted to get crazy, go for the Series 4000 touchscreen version. That's where you can
really have some fun!
All that being said, though. . . you still have to have some knowledge of this kind of thing to set it up; like the Motorola stuff, it's definitely not plug-and-play.