Can a letter of invitation and financial support substitute for the financial requirements of a METV for my girlfriend?

I have just started to consider the possibility of an METV for my gf who is currently in the Philippines for about 6 months or more, instead of our previous SETV which got rather over used.

We travel frequently by car to Malaysia, Laos , probably Singapore later on, and India on the new trans highway(day dreaming), so the METV and my Multiple re-entry permit for myself plus the temporary export permit for our car would be a great option for us.

On her own she would not meet the financial requirements so I need to know if a letter of invitation and financial support based on my Non O Visa based on retirement would substitute for the financial requirements for the METV.