-Customizable implies minimal RUP (resembling XP) possible.

-Robert Martin's dX method- use cases on index cards 

Double meaning in name:

• delta X (incremental change in RUP)

• XP upside down 

-Craig Larman [ref. 1]  also proposes "lean and mean"  RUP

• incorporate important XP practices

• eliminate practices irrelevant to "agile" development