I don't think that's a realistic option, if MS could have done it, they would have, to avoid complaints such as these. And if they the original authors can't, probably no one can, at least not affordably.
VB.Net's lack of VBA compatibility with major business applications such as Excel, Autocad, Access, and MS Word, as well as its lack of automatic error detection and correction architecture, when combined with VB.Net's lack of backwards compatibility with code from all previous versions of VB...makes for a tempting target.
Seems to me that Microsoft must have one hell of a good design on their hands, otherwise some of their largest detractors in the open source community wouldn't be trying to clone it with their "mono" environment. They claim it's a fantastic concept, from what I've read.
VB.Net makes for a poor competitor to almost any enhanced VB 6 compiler imaginable.
Depends on what you're looking for, VB.NET is much more internet savy, and more compatible with external protocols/languages. The tools and 3rd party add ons will eventually mature, it's not as long in the tooth as VB, and more complex to integrate additional features.
Bottom line, if you haven't upgraded your skills yet, I wouldn't wait much longer, because as you surely know, it's a whole new "paradigm", to use dilbertism.
If it couldn't be done, MicroSoft would happily sell the rights and code to their VB 6 engine. If it can be done, then they will staunchly refuse to ever let their VB 6 engine be bought by a 3rd party firm.
VB.Net is fine for a new firm, or for an individual programmer. On the other hand, VB.Net is a disaster for firms with large existing bases of VB 6 (or VB 5) code.
If you are writing everything from scratch, then VB.Net is fine (presuming that you don't need to interact very much with major VBA applications such as MS Word, MS Excel, MS Access, Autocad, etc.)...but if you want to leverage programming work that you paid for some years ago, forget it.
If you are going to update your skills, you should first learn what skills offer the most reward; that won't be VB.Net.
VB.Net killed the momentum that VB 6 built up from VB 5; VB.Net will not match that level of corporate interest and demand in any reasonable timeframe.
And since you have to learn a new development environment and programming architecture if you want to move from VB 6 to VB.Net, you might as well learn a new development environment and programming architecture that will be around longer, in more use, and pay more than VB.Net skills.
There are other, better options out there, after all. VB.Net isn't the only programming development environment out in the field, you know!