Yes, I did see Vesta naked eye, way back in 1989 and a very pleasant memory it is too.
We had been staying in Kalgoolie and on the way out of town checked for mail sent c\- PO. My copy of the astronomy mag was there (probably Sky and Space). That night we camped in the bush somewhere near Laverton and over dinner I read about Vesta being naked-eye (mag ~ 5.5) in Sagattarius. We had our fluoro light hanging over us but by leaning to one side and shading my eyes I thought I could see it!! After dinner I walked around the front of the car and it was very plain to see. I knew the sky well in those days and a new 'star' in such a well known part of the sky stood out clearly.
The next night we stayed in Meekatharra and the day after started our trip up the Canning Stock Route. Between long days and night time conversations around the campfire I never did see Vesta again. Thanks for reminding me of good times and perhaps I'll make an effort to see Vesta again, 26 years on.