Heidi Moore has found a June report breaking down Lehman Brothers on a sum-of-the-parts basis:

Lehman Brothers asset management alone is worth $8 billion if it is valued the same as its peers using a multiple of 20.1 times the share price to trailing-earnings since 2000, wrote David Trone of Fox-Pitt Kelton Cochran Caronia Walker on June 13. That $8 billion is pretty considerable when you consider that all of Lehman had a market value of about $13 billion when the report was written ($11.5 billion as of Tuesday). It means the core Lehman businesses-investment banking, fixed-income and equity-was valued at only about $3 billion. Combined. (The remaining $2 billion in Trone's valuation of Lehman comes from the high-net-worth brokerage business-the guys who sell Neuberger Berman's funds, among others.)