To the Gas Station idea; /fillup <amount>:
Where is the roleplay in that?
The whole point of Gas Stations is that it takes time to get your fuel and be off, not just a simple /fillup 100 and drive off.
The point of stopping your car, waiting, filling is the prime roleplay factor of Gas Stations, adding a /fillup command would destroy all roleplay.
Regards,
Gildor