here's where you can find region 1 dvds i've searched so far..
image - harrison plaza
5th avenue - park square makati
spectra - park square makati
audio visual driver int'l - edsa shangrila
expect it to be expensive, most of them set their prices at retail prices of dvds x current peso value to usd
i think the reason whay they can't be sold in most stores is that region 1 is prohibited to be sold, that's why we have region 3 releases. just a hunch