My guess, is this is worth around $250 - 300k in license revenue. plus extensive prof services. I know Marimba will discount significantly (like all the other ESD players) to get a good deal. I also know they are targeting fincnaicl services companies so Barclays fits right in and is a desirable customer to them.
I would bet Barclays looked at the others, having first realized that sms wouldn't work for them. Probably nvdm, and maybe OSA, cognet, swan or ONTC - no big company does a deal like this without evaluating several players. Knowing the trouble nvdm is in, they probably put some competitive price pressure on mrba, so I doubt they got anywhere near list price.