long words with few different letters

3, 4, 5 or 6  letters

word total
letters
different
letters
alfalfa 7 3
entente 7 3
feoffee* 7 3
meseems 7 3
referee 7 3
senescence  10  4
sleeveless  10 4
tattletale 10 4
abracadabra 11 5
endlessness 11 5
engineering 11 5
hoddy-doddy 11 5
inconcoction 12 5
senselessly 11 5
sleeplessness 13 5
uselessness 11 5
defenselessness 15 6
successlessness 15 6
insensibleness 14 6
supposititious 14 6
 

7 or more letters

word total
letters
different
letters
disinterestedness 17 7
interconnection 15 7
nationalization 15 7
nonintervention 15 7
sententiousness 15 7
unconsciousness 15 7
conscientiousness 17 8
consentaneousness 17 8
instantaneousness 17 8
reinterpretation 16 8
subconsciousness 16 8
internationalization 20 9
transubstantiation 18 9
unintelligibleness 18 9
disproportionateness 20 10
counterintelligence 19 10
incompassionateness 19 10
interdenominational 19 10
otorhinolaryngologist 21 11
interdepartmentally 19 11
indistinguishability 20 12
paleoanthropological 20 12
uncharacteristically 20 12
interchangeableness 19 12

* From Merriam-Webster's Online Collegiate Dictionary:

Main Entry: feoff·ee
Pronunciation: fe-'fE, fE-'fE
Function: noun
Date: 15th century
: one to whom a feoffment is made