The Maxon PM200 is a now-discontinued taxi/commercial radio. It is available in 2m (PM200V) and 70cm (PM200U) variants and can transmit at between 2 and 25Watts. They can be found incredibly cheap on eBay (I paid ~£10 each for mine!). Note that in the UK at least the UHF version seems to be basically nonexistent and I have only seen VHF units for sale.
Very little information exists surrounding using these for amateur applications such as packet, This Wiki page will be expanded as more investigation is done.
The following documentation and software is hosted on third party websites, at time of posting I have confirmed that all linked files are correct and safe however please perform your due diligence when downloading from unknown websites.