Alternative development tools like Navision

Hello,

I have a somewhat strange question: our backoffice is currently running a native Navision environment, which is perfectly fine for our needs. Our salespersons however, about 16 of them, need an offline application on their laptops to access some basic backoffice information like item- and customer information. Ideally they also need an environment where they can input orders when they're with the customer. It needs to be offline because mobile network is not available everywhere, especially not indoors, and the sector our company is active in implies that customer wifi networks are non-existent most of the time. Technically there really isn't a problem: our backoffice can prep some interfacing XML files like a customer- and item export and the salespersons can download them in the morning at home before they go off to their first customer. That way they have pretty accurate information with them all day. And the other way around would work to: the offline application preps XML interface files for the orders they input, and an application server server-side can import them automatically.

Now my question is: since the Navision licensing model doesn't legally allow this in an affordable way (16x €1500/user in the Business Essentials model alone makes for a whopping cost of €24.000, and that's without any custom objects), does any of you know a development environment that's similar to the way applications are developed in Navision? Something other than Microsoft Access though...

Thanks