Re cost: My girlfriend and I managed to travel South East Asia for 3 months for £1200 between us. Flights to Malaysia were £350 return each from the UK. That included travel, accommodation, eating, activities, etc...
I guess it could be done. I was there for 6 months and working, but I easily burned through $2.5k per month. Most of it on really nice accomodation though.
We usually spent 40-60% of our budget on accommodation. Our target was 30MYR in Malaysia, 250THB in Thailand, and 3USD in Cambodia. Singapore was too expensive for us to do much, so we only stayed a week, and used our whole budget every day just on a bunkbed in a hostel...
I just return from a year of traveling in SE Asia and 10 GBP per day seems like really low. Transportation alone could eat that amount easily.
My budget was something around 20/day, which buys me dorms at nice hostels (no bugs, aircon and usually hot water), food at local restaurant (I usually stays out of hawker stalls), transportation and occasional sights (like Angkor Wat and such).
Lol, we didn't have any of those luxuries... Could only afford hotels in Cambodia (3USD per night for a double ensuite!), hostels everywhere else. Only had aircon a couple of times. Never had hot water (it's 30 degrees there all the time, I never needed it). We only had restaurant food occasionally, most of the time from street stalls, or peoples houses. We only had beg bugs in KL, but we had them for the full 15 days we were there, 5 different hostels...
PS: We got a 3 day tour of all of the Ankor Wat temples, including transport between them for $9 each. For anyone who's not been, they are incredible.
12 months including places like NZ and AU for $15K isn't terrible though. Costs in SYD/MEL/AKL are higher than somewhere like BKK or KUL. $7k on flights sounded pretty high though.
We had a £10 a day budget.