It's not the perfect solution..but Medtronic has a CGM called "iPro" which is worn 3days at a time. The catch is that it's not a product an individual can buy, it's made for doctor's offices and D clinics. If your local clinic has some, you can arrange to go in, get it put on and then wear it for 3days, return it and then go over the results.
The "iPro" is different, in that you only wear it for about 3days and it doesn't give real-time results. There are no beeps, no screen to show you a graph of what your levels are doing..all of that is downloaded onto the clinic's computer once you return it.
It was recommended to me by my endo, because he didn't think I'd enjoy the CGM 24/7 and we're just looking for a pattern, which is exactly what the "iPro" is made for; to find a 3day pattern of what your levels are doing, so you can adjust insulin.
If your clinic has one, maybe that's something to look into..though it wouldn't give you the real-time warnings it sounds like you're looking for =/
I've been waiting since August for my local D Clinic to call and say they FINALLY have them in. Apparently it's been over a year since they started trying to get them in their office, I donno if it's associated to cost or the fact that Medtronic Canada is a pain to deal with (well at least in my experience of trying to get the Guardian CGM & sales rep info from them since August!) but I'm still waiting!