Be careful of any thoughts that amount to 'buying' yourself into a job or experience.
If you are just trying to break the 500 multi IFR barrier, then you might create more problems than you solve.
I know of a couple of blokes who bought into flying schools as Grade 3's who ended up in court suing their CFI/business partner. How could they have ever been 'equal' partners?
I know of a bloke who bought a Baron 55 in '94 to do what you are thinking, and he won't say so but I don't think he feels that he got any further especially with the number of dramas it caused him.
I know of at least one other bloke whose 'acorn to a big oak tree' charter business ended up in family lawsuits when all the family money 'disappeared'. The guy had 500 multi alright - 500 hours in multiple solicitors offices.
You are basically setting up your own business in an area in which you have by definition very little experience. What qualifies you to do a better job than someone who has been in light twins for decades?
Which twin? Baron, 55 or 58? C310? C402, B or C model? Aztruck? Navajo? Chieftain? Partenavia? Some are suited to different work -- short sectors of 15 to 20 minutes between islands, or running out to WA mining camps?
Clientele -- aboriginal folk or mining executives? IFR with greater capability, or VFR for lower maintenance and no enroute charges? Who will hold the maintenance approval?
Old or new(ish) airplane? Why is it for sale -- someone else trying to get rid of their millstone/money pit/bad idea? Whats on the market?
Will you form an association with a particular business or go it alone? If they think it is such a good business idea to have another twin in their fleet, then why are they not buying one themselves?
Who will supervise you as a chief pilot? Which AoC will you operate under (remember the rules got tougher on that a few years ago too)?
How will you feel if someone else runs a prop through a star picket on your day off and puts it out of action for a while?
Have you owned and operated an aeroplane before, and do you have a true understanding of how much it will really cost?
What if you solved all these problems and put it on line with an established charter outfit, who for whatever reason find it easier to indirectly use your financial resources instead of acquiring aircraft in their own right.
What if they are the people taking the phone calls and invoicing the customers and paying you, but instead of you getting your pitiful charter pilot wages every fortnight, you maybe get paid 90 or 120 days in arrears, but only after you have an argument with your 'business partner' who is busy trying to keep his own aircraft working and paying refuellers, etc, and naturally puts you, the boggie bush pilot, last.
And remember, if things go bad, YOU have to go hassle the engineers to fix your Baron instead of the other guys collection of twins and singles, while your employed 'colleagues' are merely bitching about the lack of flying while they drink coffee in the office.
And if the operator goes bust, owing tons of money left-right-and-centre, they, as employees, will get paid before you do and get better and faster treatment under the law, maybe with free legals from their union or state government dept of industry, maybe suing for underpayment of wages, while you have to chase your 10c in the dollar with a $250/hr lawyer that you pay for, no refunds, and most definitely at the end of the queue as an unsecured creditor.
What if in a year or so you have enough twin time to take the next step up the ladder but this beaut twin has two years to run on the finance and you can't find a buyer?
What if you get the multi time you want and
VB (for example) offer you a job but you can't afford the 737 endorsement coz you are mortgaged to the max to the finance company, you still have that bill for a replacement TSIO-520 but the engine shop has put a workers lien on it because you haven't paid your last bill and the guy whose line you put it on has gone into receivership owing you the last three months of charter receipts?
And how much airline interview study did you get done while all this was happening?
Stop it ITCZ, stop it stop it [stamps feet]
HOW NEGATIVE OF ME
We have all seen it before, it stops being a surprise
If you are motivated and have the resources, by all means, have a go mate, but remember that there is probably a reason why most blokes don't go that way to get multi time.