Oh, that is awesome, Dippy! I am always on the lookout for family starters as I like to add lots of families to my hoods. I think probably about 90% of starters I have seen only have one bedroom sadly.
When I made my orphanage family today, I discovered that 1 adult and 7 kids get $34,000 starting fund. So that gave me a little extra to work with when I built their home. It's not brilliant, but it's got 3 bedrooms and 3 bathrooms!
Front:
http://i196.photobucket.com/albums/aa276/elanorbreton/Sims%204%20Homes/Orphan1.png
Rear:
http://i196.photobucket.com/albums/aa276/elanorbreton/Sims%204%20Homes/Orphan2.png
Upstairs:
http://i196.photobucket.com/albums/aa276/elanorbreton/Sims%204%20Homes/Orphan3.png
Downstairs:
http://i196.photobucket.com/albums/aa276/elanorbreton/Sims%204%20Homes/Orphan4.png
There are 5 girls and 2 boys in my orphanage, hence the large girls room. I made the nicest room for the adult, she is a mean sim who sees the little orphans as her personal slaves. So she has all the best stuff and the tv. But the kids haven't done too badly.