WSP has simplified their product offerings lately. If it's been a couple years, you should check them out again.
I recently outlined a range of offerings in this area to use in marketing, starting with VI and spreadsheet import/export, then on to ROI's In-Synch, and then to WSP. The reality is that any significant integration, especially not batch-oriented, will come very close to $10k 1st yr. WSP can offer its sync tool only for ~$5k to link between your Sage 100 and , say, and existing Magento site. The b2b site is under $25k usually.
My point is that if he wants a portal, I don't see how he gets it for under $10k, and the next level up is double that. If he wants just real-time portal, it requires reporting magic and database enhancements which I don't see happening for under $5k if he's really lucky.
I know that's real money, but my immediate question is, ""How much benefit/value does he expect to generate through use of this dashboard?"" You really need to sit him down and work that out. I'm gonna guess that he has no budget for any of this right now. He needs to understand his realistic pricing options.