My current job contract with ABC Industries has a non-compete, stating that I cannot go work for a "direct competitor" until at least 2 years after my employment with ABC has concluded. Additionally, I can't take any trade secrets, patent applications, client lists, etc.; with me (i.e. don't go stealing company contact lists and customer databases).
I had a dispute about a half year ago with my boss (was promised 2 promotions plus a massive bonus and raise for excellent work, made the company a ton of money, millions per year thanks to the team I formed, trained, and led). After putting in all this work, the bonus/raises/etc. were rescinded, with no reason provided. I was given even more work, but none of the promised benefits.
While talking with one of our larger customers (CompanyInc) over a "e-lunch" meeting (monthly sales/order call), I casually mentioned that I hand-picked, formed, trained, and led the team that did all this work and generated all this extra cash for our company. The customer from CompanyInc (i.e. one of their sales engineers that I meet every month) put me in touch with their VP. I thought it was to place an order or contract renewal with my employer ABC, and it turned out to be a job offer for me, with a massive increase in benefits. My job is to "re-create the success of my previous initiative, without bringing any company secrets with me" (i.e. re-create parts of my old project without using any ABC information: re-invent it from scratch).
I have no doubt that within 8 months, I could have this project running at full speed, and within 12 months, cause ABC to be short a lot of money per year. The idea behind the product is actually dead simple, and the only reason the company is making money off of it is due to not adhering to the open source software license associated with the project (new employer already knows this, and plans to comply with the license).
My question: Is there any practical way to inform my current employer that they should pay-up, or I'll leave (and they'll lose a ton of money in the process)? I'd like to, despite all this, stay with my current company (only because new employer would require relocation to a less desirable city), but I can't think of a way that doesn't come across as an ultimatum. Is there a constructive approach to this?