How do I transfer points into Iberia?
 

I was told by Iberia that a BOS-TLV, ATH-BOS ticket on IB for $800 can be upgraded using 5500 or so IB points.

What vehicles exist to transfer points into IB's program?

Very few (maybe none). For example SPG has IB as the ONLY airline with no transfer options. IB seems to want you to earn points by flying with them; what a novel approach to FF programs. Partly they do this because of the high valuation of IB points (if they allowed spg transfers, for example, it would be at 10:1, so that would be circa 50K spg points, I suspect, and not the 1:1 of most airlines). Same applies to MR etc.

I believe you can transfer AMEX Membership Rewards points to Iberia Plus.