When I was at University, I was looking for patterns in numbers and noticed this... but this is also in the dictionary...
ya- や(8) is the translocation of yo- よ(4)
[Is mu- む(6) is the translocation of mi- み(3) ? It's not in the dictionary but feasible...]
ya-tsu 八つ= 8
ya-so- 八十= 80 (yaso-ji is also listed but also means 80 yrs old)
ya-ho- 八百= 800
ya-chi- 八千= 8000
ya-yorozu 八万= 80000
ya-ho-yorozu- 八百万= 8 million
this last one is in the dictionary... きわめて数の多いのにいうこと ("refers to a very very large number") also "”神”にかかる枕詞のように用いる" (Also used as a 'pillow word' describing the gods. - A 'pillow word' is a poetical word (Makurakotoba on wikipedia)) - example:
"ya-ho-yorozu chi-yorozu kami no, kami tsudohi tsudohi imashite" "There were billions of gods... the gods were gathering"
It wouldn't be a literal translation - (8 million, 10 million)
ya-so- 八十-(80) appears to be used for 'many' ...
- yasokuni 八十国 (many countries)
- yasoshima 八十島 (many islands)
- yasokami 八十神 (many gods)
- yasoba 八十場 (many places)
http://www.flickr.com/photos/houtoku/4246615129/ (Yasoba town)
Interestingly there's a lot about Ya- .. hardly anything about Mu- (6)...
[Under Mi- (3)... mi-so-hito-moji (31 syllables - what do you get if you add up 5-7-5-7-7 tanka? = 31) - so perhaps that answers how you join them up. Rather than "misoji mari hitotsu"]