Up until this one, the largest number of columns in a single table I'd ever seen was in a datawarehouse based (loosely) on Inmon's model. It had 403 columns.
I don't know much of anything about columnar databases, but in anticipation of HUGE performance problems based on the design I've seen (there are 80 tables in this database with an average of 750+ columns in each table), I've been talking to Sybase about SybaseIQ. I have no experience with it, but from the tad bit I know about the architecture, it might help this otherwise horrific database design.
Knowing about this data, and knowing its for a reporting system, I can't imagine the queries will be interested in more than 10-15 columns at a time out of these tables. I might be full of crap, but if columnar databases work and perform like I think they might, it could help. One thing's certain: with this design, almost nothing I can think of could possibly hurt. ;0)