Nitro, I know this is not exactly what you are looking for, but it is a place to start. Barrons has a Weekly Bond Statistics column in it's market week section. Their website may have some symbols for graphing confused: ), if not the hard copy might suit your needs in spreadsheet format.
Here is a sample:
Confidence index (high grade/intermediate grade)
Tbill/Euro$
Lehman Brothers T Bond
LB Credit index
Ryan Labs Treasury index
Bond Buyer 20 Index
Stock/Bond yield Gap.
I would also guess that you could create some synthetic indexes using closed end bond funds. WWW.ETFCONNECT.COM is a good source for these.