I think Kim would have some more valuable inight, but there are some practical reasons why I don't think we'll see much happen with this
1) a surgeon will be doing long,complex procedures with high complication rates at 50 cents on the dollar (due to mulitple procedure discounting with insurance billing). As reconstructive procedures pay worse then the resection procedures (when you account for increased complexity, decreased productivity and aftercare), I can't imagine this will ever make much financial sense
2) Oncology procedures of the breast (generally speaking) are short,simple, and predictable. Reconstructive procedures are often long, complex, idiosyncratic, and prone to reoperations. The aftercare for reconstructive patients is orders of magnitude more complex then the aftercare by a general surgeon for breast CA. As most specialty breast oncology types are trying to focus and limit their practice, adding reconstructive procedures destroys that model in terms of complexity.
3) the skill set for a lot of reconstructive procedures is the sum of a lot of highly specialized techniques that just wouldn't be able to be incorporated well in a breast-onc fellowship. It would be far,far easier to start with a trained plastic surgeron and work backwards towards a combined breast onc-reonstructive practice then vice-versa
4) the efficiency of a breast-onc practice model (like derm) relies on focused expertise and throughput of patients. Things that disrupt that undercut the financial sustainability of the model.