Elliott; upsizing the collet, even if possible, isn't a great idea. This came up in another thread today. Using a reducer doesn't add any extra load to a router designed for the heavier bits and workloading.
The opposite applies to upsizing; the bearings, motor, and arbor are being asked to withstand forces they weren't designed for.
Once you've stepped up to 1/2" sized shanks, what's to stop you from putting a massive profiling bit in there?
At the very least you'll likely overload/burn out the motor.
If you buy a new, appropriately sized 1/2" 2 1/4+ HP router from a reputable manufacturer, it won't break the bank, and you'll have it for a very long time.
A lot of the members here like Bosch, particularly for their excellent customer service, but there are certainly other highly regarded machines out there. Stay away from used ie 2nd hand! You have no idea what torture it's been through and the repairs if required, could end up costing more than a new one...plus you get a warranty with new.