I went to PSI's website and it shows that they sell a package of ten that are 10 inches long for $9.95. I went to woodturningz website and I couldn't find any 7mm tubes in long lengths. I sent them an e-mail asking if they've got them.
Ryan from Wordturningz returned my e-mail. On a Sunday, that's what I call customer service. Anyways, they sell the long lengths of 7mm tubes. A package of 10 that are 10 inches long are $9.50. Thought it was worth mentioning for future reference.