I saw one complete solid number set (with the same prefix) (1954 $1 note) plus the ten million number in Flordia during a business trip back in 2001. The dealer told me he paid US$13K to bring it in and he is selling at US$18K.
The set are:
??1111111 ??2222222 ??3333333 ??4444444 ??5555555 ??6666666
??7777777 ??8888888 ??9999999 ??10000000
Total 10 notes
From that onward, I start to collect solid number trying to build up the same prefix.
Yuman
(ps --- Arthur, if I am right, I believe you got one solid number note (6) match my (4) prefix)