Thanks folks.
I'm looking at buying a residential house at $400,000 and leaving $50k in the deal with the vendor and paying the $50k off in 3 years time. Basically, the vendor has a loan that is listed after the bank who is listed first.
While most banks won't look at vendor finance, I know this sort of deal happens out there. Sometimes they don't work out and sometimes they do work out.
Exit strategy is long term hold.