Is there any source that can provide information on the details of certain companies pension plans? For example, does the company ENRON have a cash balance plan with a lump sum option for payout?

If you use the Net, try http://www.freerisa.com for recent form 5500 filings made by the companies you are interested in.

Or you can go to the source:
http://www4.enron.com/corp/jobs/benefits.html

Apparently, Enron has a cash balance plan but the summary is very brief. BTW, it is possible, but I have never seen a cash balance plan that did not have a lump sum option.