Yup, no prob.
Mind it depends how you define 'limb' I've had some fine bows from trees where several stems shoot up from a common root, or two limbs are growing up close together (often the inner faces of those limbs will be free of branches).
I got some great Yew last Winter, first pice was about 5" diameter dead straight 7' long, it was shooting up from a trunk which had long since toppled over, in fact there was a whole row of these lovely straight shoots (mostly too thin...but give 'em 20 years
). The second piece was on a huge old spreading Yew, there was a big horizontal branch about 4 foot off the ground and this nice vertical shoot about 4" diameter going up for about 6 foot then fanning out. I took 'em both with the help of my big Sis on a bright frosty morning, followed by a pint and a bite in the local pub...glorious day.
The heart/sap ratio is a matter of luck.
Have a shufti at my website (just google 'delsbows') The bow on the home page (also featured under 'yew Longbows) is from a limb and it's my fave' bow.
Del