According to this press release from the 2004 Republican National Convention, General Motors will be the official transportation provider for the convention, and will supply the city with eight hybrid powered busses.
However, the document states that GM will also provide hybrid pickup trucks, and describes them as "highly efficient vehicles." While generous of GM, it is a complete lie that their hybrid pickups are efficient. GM's vehicles are mild hybrids, and do not get the same increase in efficiency as do other HEVs. For example, a Prius gets around double the mileage a conventional car its class gets, but the GM hybrid pickups have increased fuel efficiency by only 5% - 13%, according to the US EPA. Mild hybrid technology on a pickup does not even break 20 mpg. That certainly does not qualify as a 'highly efficient vehicle'.
It seems that both GM and the RNC are attempting to benefit from the halo effect of hybrid technology, somewhat undeservedly.