M-W unabridged:
flustrated
Etymology: fluster + -ated (as in frustrated)
: FLUSTERED

(flustrate is in Webster's 1913 edition, evidently as a var. of fluster)

edit - here are the OED citations:
1712 STEELE Spect. No. 493 {page}4 We were coming down Essex Street one Night a little flustrated. 1797 A. M. BENNETT Beggar Girl (1813) I. 106 She was, she confessed, quite flusterated at the idea. 1876 MRS. OLIPHANT Curate in Charge (ed. 5) II. iv. 100 The head of the college was slightly flustrated, if such a vulgar word can be used of such a sublime person.

editē - I think in Linguistics this is merely called a blend, which The Mavens say flustrate is not.

Last edited by tsuwm; 01/26/2007 4:24 PM.