I'd say NR, Boreray and Shetlands are roughly similar in size, Portlands a wee bit larger, but still not large.
All have fleece of interest to handspinners, by the way
. NR and Boreray more of an acquired taste, being double-coated, but popular for their colours and rarity. Portland very easy-going fleece, nice to spin, suitable for sweaters and so on. [member=11700]Tiva Diva[/member] has Portlands.
Shetlands... a good Shetland fleece is a
dream - but there are a lot of Shetland fleeces around, as the breed isn't rare, and many spinners either know a local flock that has good fleeces or just mail order one from Jamieson & Smith, the Woolbrokers on Shetland. Not to put you off the breed (I think they're wonderful), but to set your expectations.
Mind, any of these breeds' fleeces
in the city would be of interest to spinners who aren't used to being able to get fleece locally!
Sorry, I'm a bit of a fleece nut