"No ship that small has a cloaking device!"
- Captain Needa, referring to the Millennium Falcon, The Empire Strikes Back
That would seem to be yet another SW technological limitation:
Or, even better, how about the cloak from a 130 meter Romulan ship of the TOS era, installed in minutes aboard the Enterprise to cloak the ship:
(The Federation phase-cloak was no larger, and though it took two Ferengi to carry a Bird-of-Prey's cloak in "The Emperor's New Cloak"[DS9], it was also smaller than a person, and later cloaked a vessel of 1,000+ meters in size.)
Pictures speak a thousand words.
(Thanks to Graham Kennedy for the DS9 cloak info.)