Anne - I'm still a bit confused.
A quick back-of-the-envelope on the income-tax part (forgetting about the 500k checking accounts) seems to suggest that I owe virtually nothing to the US:
Assuming 300,000$ gross income, an exchange rate of 3.43 Malaysian Ringit per US$ gives 1,029,144 RM.
300,000 lies between 195,850 and 349,700, yielding US tax amounts of 43,830.50 + 33% over (300,000-195,850) = total of 78,200$
If I understand Malaysian tax brackets correctly (http://fortunesense.blogspot.com/2009/01/malaysia-individual-income-tax-rate-for.html and http://www.hasil.gov.my/lhdnv3e/individuIndex.jsp?process=21000&menu=13&expandable=1), I'd pay 54,825 RM over the frist 250,000 RM, and 27% over the remainder of 779,144 RM, equating to 265,194 RM = 77,305$ .
I'm not sure where your 30% Malaysian rate comes from, or if the 28% quoted by http://asiatax.wordpress.com/2009/06/30/malaysia-tax-and-accounting-principles-at-a-glance/ is correct. In any case, a higher Malaysian tax-rate could only help me, since my employer would pay more tax to Malaysia, which I can deduct from my US taxes, can't I?
Is the above correct, and does it indeed mean I'd have to pay an extra 78,200-77,305 = 895$ extra tax to the US over and above what I (i.e. my employer) pays to Malaysia, presuming the 27% is indeed the correct max Malyasian tax rate?