Nice model. Going to give that a go.
Does anyone know if cellphone anntennae and billboards are being combined?
If you're looking for "different" modern billboards try http://www.dribbleglass.com/subpages/strange/pictures.htm
Example
Here's a couple I made earlier, the RoadBox, copied from an idea on the PFM forum is lettered with a combination of Microscale - the Railbox logo and American Flag - and home made inkjet decals. On the actual model the blue in the logo and RoaBox appears the same.
The second was made using a...
http://www.railgraphicsdecals.com/
http://www.beldecal.com/custom_decals.cfm
http://www.microscale.com/custom.htm
http://solidesign.bizland.com/
Just a few links
Although not the contrainer version there was an article in RMC on building a Wasteliner car. Also one of the groups on Yahoo (PFM?) had a project going amongst the members. Scale Rail Graphics did decals.