Remote (with SMART Board) vs. Face to Face Design Sessions

I'm working with a team based in another location.  The product owner and I are trying to bring down one of the developers down for a collaborative design session.  We're at an important juncture and really need to hammer out some important design questions.  This developer has a focus on UI development and a rich background in human factors.

In January, I went up for a week to work with him and then then product owner.  We spent most of the week in a conference room with a whiteboard and were extremely productive since we played well off each other.

But, the powers that be are now balking at the cost ($2k or there abouts).  They want us to rent a SMART board for the developer's office (we already have one) and have the meeting remotely.

I'm estimating based on my previous experiences that we'll be 50-70% as productive and are 30-50% likely to miss something important insight.  With a SMART Board and video conferencing, we might get up to 60-80% productivity, but I'm still concerned about losing the richness of working at the same whiteboard (with a lot more whiteboard).

Anyone know of any studies of quantifiable benefit of working face to face vs. remotely with a SMART Board?  What do you think the increase / decrease in productivity will be for face to face vs using an interactive whiteboard, teleconference, and video conference?

Thanks,

Ron