Is there Maine law restricting the re-sale of cemetery lots?

Yes. Sale of cemetery lots for speculation or investment is clearly against the law. Maine statute states:

The sale of cemetery lots and plots, or the sale of crypts in a community mausoleum or niches in a columbarium for speculative or financial investment purposes, or the conveyance of any portion of a cemetery already dedicated to burial purposes as security for debt, is prohibited. Every such conveyance, whether made by a person or by a cemetery association, or by a company or association owning and operating a community mausoleum, crematory or columbarium, or by any holding, development or subsidiary company, shall be void and of no effect. 13 M.R.S.A. §1304

Violation of this statute is a misdemeanor. Moreover, any proceeds from such a sale must be applied “solely to the management, superintendence, improvements and maintenance of the cemetery.” 13 M.R.S.A. § 1305. Funds must be applied first to liquidation of debt and any residue deposited into a fund for permanent care of the cemetery. Id.

Therefore, Maine law prohibits the resale of cemetery lots for any for-profit sale, other than for the purposes of retirement of debt or permanent care and improvement fund.