In the two years since these renderings first appeared, not much has been going up on the site of the proposed Lakeside Center project in Prospect Park?except for the price tag. The cost of the Tod Williams Billie Tsien Architects-designed facility is now estimated to be around $70 million, up from the original $50 million. And even though not all of the money has come in yet, according to the Brooklyn Paper, local politicians felt yesterday was as good a time as any to break out the ceremonial shovels. Eventually, a 26,000-square-foot building will stand on the site, with indoor and outdoor skating rinks. Hey, ice skating rinks are hot right now.