I've been intrigued with Shiraz (Syrah) and Viognier co-fermented blends awhile.
I've noticed they vary widely in the percentage of Viognier added to the blend -- anywhere from 2% to 18% -- and that makes a huge difference in the finished wine.
A small percentage has little effect and seems more for color stabilization and a nod to tradition; a large percentage can make the wine cloyingly aromatic (jasmine tea, rose petals) even to the point of smelling "candy-fied."
Meng's rec is good: d'Arenberg is perhaps the best Oz producer.
Yalumba in AZ (mentioned several times below) makes a few co-fermented Shiraz-Viogner blends:
Handpicked Shiraz + Viognier $25
Barossa Eden Shiraz Viognier $15
Y Series Shiraz Viognier $10-11.
Also, check out Yering Station, Kangarilla, and Henry’s.
In the US, the blends are higher in price. I'd probably turn first to Rosenblum's blend and to those of some of the smaller Paso Robles, Santa Maria and Santa Barbera producers. Some of these may be a bit beyond your budget but are worth trying if your wallet will allow it. Here's my list:
Rosenblum Syrah Rominger $18-22
Ridge Syrah Lytton West $35
Andrew Murray Roasted Slope $31
Spring Mountain $40 -- 18% Viognier
Mcprice Colson Canyon $20
Ampelos Syrache $28
Arrowood Saralee's Vineyard Syrah $34