Hmmmm...
well, I would have to say its not going to be cheap.
What your going to have to consider here is the fact that this is a money transfer application, so there goes a ton of programmers you would have had, because few people want to get mixed up with money stuff. (too much liability).
So your largest problem will not be your interface, nor anything else you requested, but security. I am sure you and your programmer(s) can talk it out, but just to let you know, your going to want a good security program.
also make sure you get a knowledgeable programmer because anyone can set up a php nuke site, thats why they make premade software like that, for people who have very little free time or dont know PHP.
I am not sure about this, but you may want to go to php nuke and make a request of them also, because if you like their interface then it would be best if it was them who did your site, because some of the stuff you want will require a wee bit of recoding on phpnuke.
but anyways, if I were going to be building your site then I would not use php nuke, I could build you a site exactly like it (but in my experience it will not be exactly like it, thats why premade stuff is not cool to use). The security, new site, design, administrative interface, ect would be around 3-4 thousand dollars (which is a great deal). But then I would also either require that you have insurance on your business, or sign an agreement that i am not responsible for anyone hacking into your site ect.. but only if it through a coding error of my own.
(I've had people try and blame stuff on me because their idiot sys admin was...well an idiot, and their site was hacked).
well anyways thats my 2 cents, looks like nobody responded to you, so i figured I'd say something.
-=Levi=-