yea, stay away from the conversions. If you want an eco-sol, get one made to use the ink, it's going to be made with better materials the entire way through. If you have to trust someone to come out and do a conversion, who knows if the conversion will include all ink feed lines, which may end up corroding due to the harsher inks. Let's not forget about cleaning the heads, are the aqueous cleaning stations going to have enough vaccuum to get all the hardened ink particles out of the solvent heads? Also, how will the printer interpret the color? Aqueous ink tends to have a larger color gamut, so it may put together a color, that would be a red color with aqueous inks, but come out an ugly brown or gray color with eco-sol inks. ANOTHER point to think about is, no one media company is going to support conversion printers, so when you go to download their scientifically researched icc profile, and you find out there is no support for your frankenstein large format printer, you will definately be wishing you had bought the eco-sol printer, so you can have scientifically researched icc profiles, with almost no color matching involved, and no having to create your own icc profiles.
so, as you can tell, i'm on the "go for the eco-sol printer" side.