Even if you step up to 8x10 in the near future, have you considered film availability in that size in Venezuela? What size ia readly available for your needs?

Here is my suggestion. You could buy a nice and cheaper 4x5 enlarger abroad, ask the seller to ship by "surface" (this is basically mailing it via an ocean going vessel). Make sure the seller insures it and gives you tracking number. At most it will take a month or so to South America (I ship stuff to Africa frequently and takes longer).

In the meantime you keep on shooting and developing your 4x5 negs. BTW, because it is a used enlarger, customs duties will be reasonable as the price will be cheap. I hope this provokes new thinking to keep shooting 4x5.

Good luck and Happy New Year,

Tautatis.